Patent Grant
8469348
The present application is based on Japanese Patent Application No. 20011-003762 filed with Japanese Patent Office on Jan. 12, 2011, the entire content of which is hereby incorporated by reference.
1. Technical Field
The present invention relates to an image forming system provided with a plurality of overlapping sections which overlap multiple printed sheets for making a bundle of sheets and convey the bundle of sheets toward a post processing apparatus.
2. Background Technology
An image forming apparatus, such as an electrophotographic image forming apparatus, to form images on sheets with high speed, is enabled to provide an image forming system attending a wide variety of user needs, by being connected with a post-processing apparatus having various post-processing functions.
Such the image forming system, being capable of various post-processing, can be utilized in light printing field. In that case, producing a large number of processed sheets in unit time period (hereinafter referred as productivity) is required. And in many cases, the number of processed sheets of the image forming system is determined by a capacity of the post-processing apparatus rather than a capacity of the image forming apparatus.
To be more specific, in the post-processing apparatus, since there are many cases of executing the processing by temporarily stopping the conveyance of sheet, it is required to ensure a sufficient sheet interval when continuously ejecting the sheets from the image forming apparatus. As a measure to this case, conveyance speed in the post-processing apparatus is made higher than the conveyance speed in the image forming apparatus. However, in high speed technology of recent years, since the conveyance speed of the image forming apparatus is increasing, the increase of conveyance speed in the post-processing apparatus is coming near to a limitation.
In Patent document 1 (JP 2007-156406A) an apparatus is disclosed, which is provided with an overlapping section to accumulate a plurality of sheets in an intermediate conveyance unit disposed between an image forming apparatus and a post-processing apparatus, and concurrently conveys the plurality of accumulated sheets. In this way, by concurrently conveying the plurality of sheet in the overlapped state, the time to convey the sheets to the post-processing apparatus is delayed by the number of overlapped sheets. Thus, by lengthening the substantial sheet interval without increasing the conveyance speed, total productivity of the image forming system is improved.
In order to further improve the productivity, the conveyance speed of the image forming apparatus may be increased, and in order to execute various complex post-processing, the required processing time period may be increased. In these cases, the sheet interval is required to be increased.
According to the Patent Document 1, the substantial sheet interval is increased by overlapping the plurality of sheets, and in order to further ensure the longer sheet interval, it is required to increase the number of overlapping sheets. However, increasing the overlapping sheets to increase the number of sheets to be concurrently conveyed may cause to detract the stability and alignment in sheet conveyance, which may cause degradation of quality in the bookbinding. Further, in cases of thick sheets or sheets of smooth surface, it is difficult to increase the number of overlapping sheets.
In view of these problems, an objective of the present invention is, by increasing the number of overlapping sheets, to provide an image forming system capable of maintaining the stability and quality of sheet conveyance, as well as achieving the improvement of total productivity in the image forming system.
To achieve at least one of the abovementioned objects, an image forming system reflecting one aspect of the present invention includes:
an image forming section to print on sheets based on a print job including a plurality of page image data;
a conveyance path through which the sheets printed by the image forming section are conveyed;
a post-processing section which executes post-processing to form a booklet from a plurality of sheets conveyed through the conveyance path as a set unit;
a plurality of overlapping sections each of which is disposed between the image forming section and the post-processing section, makes the sheets temporarily wait, forms a bundle of sheets by overlapping a plurality of waiting sheets with each other, or by overlapping the waiting sheets with a sheet being conveyed through the conveyance path, and conveys the formed bundle of sheets to the post-processing apparatus;
a control section which, with respect to a second or later booklet set in case of continuously forming a plurality of booklet sets, controls a number of the plurality of sheets to be conveyed to the overlapping section, a conveying order of the sheets, and a timing to convey the formed bundle of sheets to a downstream side, based on a period of executing the post-processing by the post-processing section.
The image forming system reflecting another aspect of the present invention is the system described above, wherein the control section controls to convey the sheets out of the overlapping sections in sequence from an overlapping section disposed at a most downstream side in a conveyance direction, corresponding to the conveying order of the sheets to be conveyed to the post-processing section.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings in which:
a-5b5 are schematic diagrams to describe a sheet conveyance control with respect to the overlapping section st in a configuration of m=2 sheets, and n=2 units of overlapping section;
a-6b7 are schematic diagrams to describe a sheet conveyance control with respect to the overlapping section st in a configuration of m=3 sheets, and n=2 units;
a-7b are subroutines of step S8 in a configuration of m=32 sheets, and n=2 units;
a-9b5 are schematic diagrams to describe a sheet conveyance control with respect to the overlapping section st in a configuration of m=2 sheets, and n=2 units of overlapping section in the second embodiment;
a-10b7 are schematic diagrams to describe a sheet conveyance control with respect to the overlapping section st in a configuration of m=3 sheets, and n=2 units in the second embodiment;
a-11b are subroutines of step S8 in a configuration of m=3 sheets, and n=2 units in the second embodiment; and
Hereinafter, embodiments of the present invention will be described, however the present invention is not restricted to the embodiments.
[Image forming Apparatus A]
Image forming apparatus A is provided, in an upper part, with automatic original document conveyance device 1 and image reading section 2, and the lower part is configured with a main body of the image forming apparatus.
In the image forming apparatus main body, code 3 indicates a sheet feeding tray to accommodate the sheet P. In image forming section 5 which forms a toner image on photosensitive member 4 by utilizing an electrophotographic process to perform charging, image exposing and development onto the photosensitive member 4, an image is formed on the sheet P, and the formed image is fixed by fixing unit 6. Fixing unit 6 forms a nip to convey the sheet P with heating roller 6b and pressure roller 6c. In heating roller 6b, heat source 6a is installed, and by controlling the heat generation amount of the heat source with using a temperature sensor (not illustrated), the heat roller 6b is controlled to be a certain temperature. While conveying the sheet P through the nip of fixing device 6, by melting the toner with heat-pressure, the toner image is fixed on the sheet P.
The sheet P is supplied from sheet feeding tray 3 to first feeding section 3a, and after temporarily stops at second feeding section 3b, conveyed and printed (image formation). The printed sheet P is ejected from an ejection slot by ejection roller 8.
As conveyance paths of the sheet P, provided are: sheet feeding path 7 from sheet feeding tray 3 to image forming section 5, conveyance path 9a from image forming section 5 through fixing unit 6 and ejection roller 8 to the ejection slot, and double face conveyance path 9b which reverses and switchbacks the sheet and conveys again to the sheet feeding path 7.
Code tp indicates an operation display section, which is configured with a display section of a liquid crystal panel arranged to superpose a touch screen. Through operations of the operation display section st, a user can set a setting of image forming apparatus A and a setting of output mode of post-processing apparatus C. Further, the user can set a paper weight and thickness of the sheet P, information of paper type and the like through the operation display section st.
[Intermediate Conveyance Apparatus B]
The sheet P ejected from the image forming apparatus A is conveyed to post-processing apparatus C through intermediate conveyance apparatus B.
In
In case of directly conveying the sheet carried-in from image forming apparatus A, the sheet is conveyed through bypath conveyance path 120. In case of conveying by overlapping multiple sheets, by conveying two sheets of p1 and p2 respectively to branch conveyance paths 121 and r22, allowing to temporarily wait at each branch conveyance path, after that, by starting to convey the two sheets with synchronized timing, the sheets are overlapped such that each leading edge coincides with each other at a confluence site in the downstream side. The two sheets are conveyed to a subsequent post-processing apparatus C and the like, as a bundle set in an overlapped state.
In the example of
[Post-Processing Apparatus C]
Post-processing apparatus C as a post-processing section executes various post-processing on the sheet P which is carried-in as a set of sheets after being ejected from image forming apparatus A and overlapped with multiple sheets by intermediate conveyance apparatus B to be the set of sheets. Post-processing apparatus C exemplified in
In post-processing machine C, first sheet ejection tray 40, processing tray 60 and staple section 50, are provided in sequence from upper side.
At processing tray 60, the sheet P printed by image forming apparatus A is temporarily stacked to form a bundle of sheets. After performing a vertical alignment process and width alignment process perpendicular to the vertical direction onto the sheets stacked on processing tray 60, staple section 50 performs a stapling process with a unit of set on the bundle of sheets to form a booklet. In processing tray 60, the sheet is stacked such that the surface printed by image forming apparatus A (the second surface, in the case of double side printing mode) comes to down side, and on the stacked sheet, a subsequent sheet is further stacked.
In
[Control Block]
In image forming apparatus A, 100A being a CPU to execute overall various control of image forming apparatus A and the total image forming system. 101A is a ROM which stores various programs and data such as programs and data for controlling image forming apparatus A. 102 is a RAM as a memory section, being used by the CPU 100A as a work area, and temporarily stores the programs and data which are necessary for CPU 100A to control image forming apparatus A, and the like.
103A is a communication section to function as a communicating means, being connected with respective communication sections 103B and 103C of intermediate conveyance apparatus B and post-processing apparatus C, to execute communications. Through said communication section 103A, the required time for processing by post-processing apparatus can be obtained. 104A is a bus to connect ROM 101A, RAM 102A, communication section 103, and the like with each other. 105A is a conveyance section to convey the sheet by controlling the operations of a driving motor, a conveyance switching gate, and the like.
Conveyance section 105B of intermediate conveyance apparatus B executes the switching of sheet conveyance path and sheet conveyance by controlling the drive motor and switching gates g1 and g2. Other sections 100B-105B of the intermediate conveyance apparatus B and 100C-105C of the post-processing apparatus C correspond respectively to 100A-105A of the image forming apparatus A, and similarly function. CPU 100A or a combination of CPU 100A and CPU 100B works as a control section.
Next, a control flow will be described.
In step S1, setting of the printing order is executed.
Table 1 shows an example of setting the printing order, which shows the page number of page image data, to be printed by the image forming apparatus A, corresponding to the sheet to be sequentially printed from the first page (1p) in each set of second or subsequent set to j-th set (jp).
In the example shown in Table 1, which is an example of single side mode to print on one side of the sheet in the embodiment shown in
In the first embodiment, as shown in Table 1, on the first sheet (1P), the data of first page of the page image data is printed, and on the second or subsequent sheet, printing is executed by the page order of the page image data, and ejected from the image forming apparatus A with this order. In the first embodiment, since the setting of printing order is same as the case of not executing the overlapping process, the process of step S1 may be substantially omitted.
In step S2, image forming apparatus A prints on the sheets by the order shown in Table 1 having been set in step S1, and ejects toward intermediate conveyance apparatus B.
IN step S3, the control section determines whether or not it is the second or later set of bookbinding process to be executed by post-processing apparatus C. Wherein the “set” means a unit for executing the post-processing, for example in a case of forming 10 sets of booklets by assuming a unit to be 50 sheets and using 500 sheets of paper, among the sheets ejected from the image forming apparatus A to the intermediate conveyance apparatus B, the sheets from first to 50th become the first set of sheets, and the second or later set includes the 51st and subsequent sheets.
In the present embodiment the sheet is overlapped at the overlapping section st, in order to avoid that the subsequent sheet is conveyed into the post-processing apparatus C in the act of executing the post-processing. Therefore, if it is the second or subsequent set (step S3: Yes), it becomes an object to be executed with the overlapping process, and the flow proceeds to step S4.
In step S4, the control section determines whether or not the number of sheets ejected from the image forming apparatus is a total number of overlapping sheets or less. Wherein, the total number of overlapping sheets is the total number of sheets to be overlapped by all the overlapping sections st. In the control flow shown in
On the other hand, if No in step S3 or step S4, without executing the overlapping process, in step S5, the sheet P is conveyed to bypath conveyance path r20 from every overlapping sections st to pass through.
In step S4, if it is before reaching to the total number of overlapping sheets, the flow goes to step S6. In step S6, the control section selects the overlapping section st to be allocated with the sheet among the plurality of overlapping sections.
Onto the overlapping section st(k), which being k-th overlapping section from the most downstream side among the plurality of overlapping sections st, the sheet formed with the image of page image data shown in Expression (1) described below is allocated (1≦k≦n).
{m×(k−1)+1}˜(m×k) Expression (1)
Tables 2 and 3 show the number order (p) of the sheet to be allocated to each overlapping section st, and the page number of the page image data (pd). For example, if the maximum number of sheets m=2 and the number of overlapping sections st n=2, the sheets to be allocated to the overlapping section st1 (k=1) are the sheets formed with the page image data from 1st page to 2nd page (pd1˜pd2), and the sheets to be allocated to the overlapping section st2 (k−2) are similarly the sheets formed with the page image data from 3rd page to 4th page (pd1˜pd2). In a case where m=3 and n=2, (p) and (pd) they become as shown in Table 3.
a-5b5 are schematic diagrams to explain the conveyance control of the sheet with respect to the overlapping section st in configuration of m=2 sheets, and n=2 units.
a is a schematic diagram showing the total flow, where the first and second sheets respectively printed with the page image data of first and second pages are allocated to the overlapping section st1, and the third and fourth sheets respectively printed with the page image data of third and fourth pages are allocated to the overlapping section st2. While, as shown in the above described flow step S5, the fifth or subsequent sheet in the set is conveyed through bypath conveyance path r20 and is passed through the overlapping section st.
b
1-
By the processes of
Similarly,
Returning to the description of
a and 7b are subroutines of step S8 in the configuration shown in
In the step S81 of
The process of step S83 and the subsequent step relate to an odd number process to be executed in cases where number of sheets in the set is less than the total number of overlapping sheets (m×n). In the case when number of sheets in the set is less than the total number of overlapping sheets (m×n), and the control section determines that the subsequent sheet is not conveyed to the overlapping section st1 (step S83: No), in the step S841, the sheets are made wait during the sheet interval Ti for two sheets (Ti×2), and after the elapse of said waiting period, the sheets in the waiting area are ejected.
The flows to be executed in the overlapping section st2 shown in
Ti×(m−1)×(n−k) Expression (2)
In the odd process of step S842, the sheets are made wait during the sheet interval Ti multiplied by the number of sheets, calculated by the expression (3) below, and ejected in a bundle. Wherein, in the Expression (3), “jk” is a variable (1≦jk≦m) corresponding to the number of sheets stacked for waiting in the overlapping section stk at the time of determination in the step.
Ti×{(m−1)×(n−k)+m−jk} Expression (3)
The processes of waiting periods in the steps S821 and S822 of
Returning to the explanation of
According to the present embodiment, in the image forming system where the control section is capable of totally controlling a plurality of overlapping sections st as a unit, by controlling a number of the plurality of sheets being conveyed to the overlapping section, an order of conveying the sheets, and a timing to convey the formed bundle of sheets to a downstream side, based on a period of executing a post-processing by the post-processing section C, the effects described below can be achieved.
Next, the control flow of the second embodiment will be described. In the second embodiment, a printing order of page image data of a print job is changed, and corresponding to the change, controlled are the number of sheets to be conveyed into each overlapping section st, the order of conveyance, and the timing to convey the formed bundle sheets toward the downstream side. In the second embodiment, the control flow of
In the second embodiment, the setting of printing order is also executed in the step S1. Tables 4 and 5 are examples of printing order setting, and shows the number of page in the page image data to be printed by the image forming apparatus A, corresponding to the sheets to be printed in the order from first sheet (1P) to j-th sheet (jp) of the second or later set.
In the second embodiment, according to maximum number of sheets m and number of units n, the printing order of the page image data is changed. Table 4 shows a setting example in the configuration of m=2, and n=2, and Table 5 shows a setting example in the configuration of m=3, and n=2. Wherein, in Table 4 and Table 5, the range of equal to or less than the total number of overlapping sheets (in the example of the Tables: m×n) is the subject region of printing order setting (the fourth or previous sheet in Table 4, and the fifth or previous sheet in Table 5). The region later than the total number of overlapping sheets (5-th or later sheet in Table 4, and 7-th or later sheet in Table 5) are not the subject region of changing the printing order. In the non subject region, the printing order and the page number in the page image data coincide with each other.
With respect to the steps S2 to S5, the processes are similar to those in the first embodiment, and the explanation is omitted. In the step S6, the selection of allocating to which of the plurality of overlapping sections is executed, and in the step S7, the sheet is stacked to wait in the overlapping section selected in the step S7.
In the step S6, onto the overlapping section st(k), which being k-th overlapping section from the most downstream side among the plurality of overlapping sections st, the sheet formed with the image of page image data shown in Expression (1) described below is allocated (1≦k≦n).
{m×(k−1)+1}˜(m×k) Expression (1)
In the first and second embodiments, Expression (1) is common, and the sheets formed with the image of the same page image data are allocated to the same overlapping section st. However, as being clear from comparison of Table 1 and Table 4, the printing order of each page image data is different, and corresponding to this, the order of allocation of the sheets conveyed from the image forming apparatus is different. By referring to Tables 6 and 7, and
Tables 6 and 7 are respectively corresponding to Tables 2 and 3, showing the order number (p) of the sheets to be allocated to each overlapping section st, and the page number (pd) of the page image data.
For example, in the case where the maximum sheet number m=2, and the number of overlapping sheets n=2, as shown in Table 6, the sheets to be allocated to the overlapping section st1 (k=1) are the first and third sheets (1p and 3p) formed with images of the page image data of first to second page (pd1 to pd2), and the sheets to be allocated to the overlapping section st2 (k=2) are the second and fourth sheets (2p and 4p) similarly formed with images of the page image data of third to fourth page (pd3 to pd4).
a is a schematic diagram showing the total flow, where as shown in Table 6, the first and third sheets respectively printed with the page image data of first and second pages are allocated to the overlapping section st1, and the second and fourth sheets respectively printed with the page image data of third and fourth pages are allocated to the overlapping section st2. While, as shown in the above described flow step S5, the fifth or later sheet in the set is conveyed through bypath conveyance path r20 and is passed through the overlapping section st.
Similarly in
As the other example, the setting example of printing order in the configuration of m=2 and n=3 is shown in Table 8, and the relationship between the order of sheet (p) to be allocated to each overlapping section st and the page number (pd) of the page image data is shown in Table 9. As shown in Table 9, the sheets to be allocated to the overlapping section st1 (k=1) are the first and fourth sheets (1p and 4p) formed with images of the page image data of first to second page (pd1 to pd2), the sheets to be allocated to the overlapping section st2 (k=2) are the second and fifth sheets (2p and 5p) formed with images of the page image data of third to fourth page (pd3 to pd4), and the sheets to be allocated to the overlapping section st3 (k=3) are the third and sixth sheets (3p and 6p) formed with images of the page image data of fifth to sixth page (pd5 to pd6).
In the step of S8, the ejection process of overlapping sections st is executed. The subroutine of said step S8 in the second embodiment is shown in
a and 11b are subroutines of step S8 in the configuration shown in
Different from the first embodiment as shown in
With respect to the odd number processes of step S83 and later, all the processes in
According to the second embodiment, in addition to the effects of first embodiment, the control flow regarding the sheet ejection process can be made common to every overlapping sections st, which enables a further simple control compared to the first embodiment to avoid the increase of development cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-003762 | Jan 2011 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5060928 | Vits | Oct 1991 | A |
| 6199850 | Seki | Mar 2001 | B1 |
| 6332606 | Seki | Dec 2001 | B1 |
| 7946582 | Suh | May 2011 | B2 |
| 20080106032 | Kanda | May 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 2007-156406 | Jun 2007 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20120175835 A1 | Jul 2012 | US |
